The major objective of this project is to investigate the morphological and cytochemical basis for cataract induction. Feeding of galactose provides a mechanism to study the induction as well as reversal to cataracts. Light and electron microscopic studies will be conducted to evaluate morphological, histo- and cytochemical changes which accompany the process of galactose cataract induction and partial reversal in rat lenses. Some of the major enzymes which will be localized at the ultrastructural level will include Na-K-ATPase and acid phosphatase. As Na-K-ATPase has been demonstrated to play an important role during cataractogenesis, this investigation will allow us to determine whether it is possible to demonstrate quantitative changes in this enzyme in cataractous lenses during the induction and reversal phase. Localization of acid phosphatase will allow us to elucidate the role of hydrolytic enzymes in the removal of tissue debris which results from their damage during cataractogenesis. Presence of a mechanism for the removal of debris would seem to be an essential prerequisite for the restoration of tissue transparency. The long term goal of this project is to find ways of preventing sugar cataracts.